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Optimal Coordination of Transportable Power Sources and Repair Crews for Service Restoration of Distribution Networks Considering Uncertainty of Traffic Congestion

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Journal of modern Power Systems and Clean Energy 2024年第1期12卷 189-201页

作者： Zhao shi Yan Xu Dunjian Xie shiwei Xie Amer m.Y.m.Ghias Nanyang Technological University Singapore the School of Electrical Engineering and Automation Fuzhou UniversityFuzhou 350108China

This paper proposes a new method for service restoration of distribution network with the support of transportable power sources(TPSs)and repair crews(RCs).Firstly,a coupling model of distribution networks and vehicle routing of TPSs and RCs is proposed,where the TPSs serve as emergency power supply sources,and the RCs are used to repair the faulted *** the uncertainty of traffic congestion,the probability distribution of the travel time spent on each road is derived based on the Nesterov user equilibrium model,and a two-stage stochastic program is formulated to determine the optimal routings of TPSs and *** efficiently solve the proposed stochastic mixed-integer linear program(mILP),a two-phase scenario reduction method is then developed to scale down the problem size,and an adaptive progressive hedging algorithm is used for an efficient *** effectiveness of the proposed methods and algorithms has been illustrated in a modified IEEE 33-bus system.

关键词： Service restoration distribution network traffic uncertainty transportable power source repair crew stochastic program

mechanisms behind the environmental sensitivity of carbon fiber reinforced polytetrafluoroethylene(PTFE)

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Friction 2024年第5期12卷 997-1015页

作者： Pontus JOHANSSON P.mARKLUND m.bJORLING Y.shi Division of machine Element LuleåUniversity of TechnologyLuleåSE-97187Sweden

Carbon fiber reinforced polytetrafluoroethylene (CF/PTFE) composites are known for their exceptional tribological performance when sliding against steel or cast iron in inert gas environments. Compared to experiments in humid air, about an order of magnitude lower wear rate and several times lower coefficient of friction have been reported for tests conducted in dry nitrogen and hydrogen. moreover, trace moisture has been shown to affect the friction and wear significantly of this tribosystem, although a possible effect of oxygen cannot be ruled out due to uncertainties regarding the oxygen concentrations. While several studies have pointed out the environmental sensitivity of CF/PTFE, the understanding of the underlying mechanisms are very limited. The objective of this research is to investigate the individual and combined effect of oxygen and moisture on the tribological behavior of CF/PTFE sliding against steel. Additionally, this study aims to elucidate the underlying mechanisms that govern the environmental sensitivity of the system. Climate-controlled three-pin-on-disc experiments were conducted in nitrogen atmospheres at various concentrations of oxygen and moisture. The tribological results clearly demonstrate that both moisture and oxygen contribute to increased friction and wear. However, the adverse effect was much more pronounced for oxygen than moisture. A qualitative method was developed to estimate the tribofilm coverage on the CF/PTFE surface. Results showed strong correlation between high coverage of strongly adhered tribofilm and low wear rate. moreover, a loosely adhered tribofilm was observed on top of the CF/PTFE surface in presence of moisture. FTIR analysis indicated that the loosely adhered tribofilm found in the moisture-enriched environment contained a significant amount of adsorbed water, which may explain the lower coefficient of friction in presence of moisture compared to oxygen. The adsorbed water in the loosely adhered tribofilm coul

关键词： polymer composite tribofilm tribochemistry atmosphere

matrix orthogonal polynomials,non-abelian Toda lattices,and bäcklund transformations

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Science China mathematics 2024年第9期67卷 2071-2090页

作者： shi-Hao Li Department of mathematics Sichuan UniversityChengdu 610064China

A connection between matrix orthogonal polynomials and non-abelian integrable lattices is investigated in this *** normalization factors of matrix orthogonal polynomials expressed using quasideterminants are shown to be the solutions to the non-abelian Toda lattice in semi-discrete and full-discrete ***,with a moment modification method,we demonstrate that the b¨acklund transformation of the non-abelian Toda lattice given by Popowicz(1983)is equivalent to the non-abelian Volterra lattice,whose solutions can be expressed using quasi-determinants as well.

关键词： matrix orthogonal polynomial non-abelian Toda lattice backlund transformation quasideterminant technique

CONVERGENCE ANALYSIS OF NONCONFORmING QUADRILATERAL FINITE ELEmENT mETHODS FOR NONLINEAR COUPLED SCHRODINGER-HELmHOLTZ EQUATIONS

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Journal of Computational mathematics 2024年第4期42卷 979-998页

作者： Dongyang shi Houchao Zhang School of mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China

The focus of this paper is on two novel linearized Crank-Nicolson schemes with nonconforming quadrilateral finite element methods(FEms)for the nonlinear coupled Schrodinger-Helmholtz *** L^(2) and H^(1) estimates of orders O(h^(2)+τ^(2))and O(h^(2)+τ^(2))are derived respectively without any grid-ratio condition through the following two *** is that a time-discrete system is introduced to split the error into the temporal error and the spatial error,which leads to optimal temporal error estimates of order O(τ^(2))in L^(2) and the broken H^(1)-norms,as well as the uniform boundness of numerical solutions in L^(∞) *** other is that a novel projection is utilized,which can iron out the difficulty of the existence of the consistency *** leads to derive optimal spatial error estimates of orders O(h^(2))in L^(2)-norm and O(h)in the broken H^(1)-norm under the H^(2) regularity of the solutions for the time-discrete *** last,two numerical examples are provided to confirm the theoretical ***,h is the subdivision parameter,and τ is the time step.

关键词： Schrodinger-Helmholtz equations Nonconforming FEms Linearized Crank-Nicolson scheme Optimal error estimates

Soils in extraterrestrial space: Need for studies under microgravity

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Pedosphere 2024年第1期34卷 13-14页

作者： m.b.KIRKHAm Department of Agronomy Kansas State UniversityManhattan KS 66506USA

With the increased interest of plants in space, gravity cannot be ignored when studying soil-plant-water relations. Therefore, it is important to understand the water relations of soils under zero gravity in space or under reduced gravity on the moon or mars. This paper outlines the problems of moving water in soils under zero gravity or microgravity, as well as growing plants in these soils. It is suggested that microgravity experiments could be done on Earth using both soils and plants. Results from such experiments could be used to grow plants when mankind establishes bases on the moon and mars.

关键词： soils soil bases

Vortex identification based on the Liutex method and its effect on fish passage upstream

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Journal of Hydrodynamics 2024年第1期36卷 130-141页

作者： Chun-ying Shen Rui-guo Yang Xiao-tao shi ming-ming Wang shi-hua He Faculty of Electrical Power Engineering Kunming University of Science and TechnologyKunming650500China Hubei International Science and Technology Cooperation base of Fish Passage China Three Gorges UniversityYichang443002China Shanghai Investigation Design and Research Institute Co.LtShanghai200434China

Fishway research is important for mitigating the fragmentation of river habitats caused by hydraulic *** vertical slit fishway is a broadly used fishway type because of its high efficiency and adaptability to water ***,the resulting vortex current disrupts the fish passage hence directly affecting fish *** study aims to accurately capture the vortex structure in the fishway and analyze the effect of vortex elements(vortex structure,vortex intensity,etc.)on *** conducted an analysis of the 3-D current flow field in the fishway through the utilization of an experimental model and the large eddy simulation(LES)***,we captured the vortex information in the fishway at different flow rates using the Liutex vortex identification method and investigated the effect of the vortex on fish *** results revealed that the structures inside the fishway pool occupy most of the room,however,the areas with higher vortex strength were primarily located in the vortex near the vertical seam and the mainstream,the vortex strength inside the fishway gradually increases with increasing flow,suppressing fish *** experienced significantly increased resistance when encountering strong *** suggests that the vortex may act as a physical barrier to fish *** findings highlight the potential negative effects of vortex on fish movement and reiterate the importance of understanding vortex dynamics for aquatic environmental *** an effective tool for identifying vortices in fluid flow,the Liutex method demonstrates features of vortex within the fishway,thereby providing important insights into the interaction between fluid dynamics and aquatic organisms.

关键词： Vertical slit fishway vortex identification method Liutex large eddy simulation(LES) fish experiment computational fluid dynamics

Large magnetostriction of Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites in a wide temperature range

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Journal of Rare Earths 2024年第4期42卷 705-709页

作者： Hehe Ding Yangguang shi Shaolong Tang mIIT Key Laboratory of Aerospace Information materials and Physics Department of Applied PhysicsNanjing University of Aeronautics and AstronauticsNanjing210016China National Laboratory of Solid State microstructures Nanjing UniversityNanjing210093China

We report the magnetostrictive performance of the Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy *** of m?ssbauer spectra and the XRD results indicate that the easy magnetic direction of the Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)compound is alongdirection with spontaneous magnetostrictionλ111 of1900 ***-oriented Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites with particle volume fractions of20 vol%-55 vol%were *** measurements demonstrate that the composite is highly *** raw material cost of Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)is about 85%of that of the Terfenol-D(Tb_(0.3)Dy_(0.7)Fe_(2))***_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites possess comparable magnetostriction with those composites made of Tb_(0.3)Dy_(0.7)Fe_(2)*** room temperature,the magnetostrictionλ_Ⅱof the Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composite reaches 420 ppm at a low field of 80 kA/m and about1000 ppm at 239 kA/*** addition,the composite exhibits a large saturation magnetostrictionλ_Ⅱover1200 ppm from 300 to 100 K,suggesting its potential applications as a low-cost magnetostrictive material in a wide temperature ***,the current study offers an opportunity to widen the operating temperature range of the magnetostrictive composite.

关键词： magnetostrictive composite Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93) Wide temperaturerange Laves phase Rare earths

Lithospheric strength of the Anatolian plateau and implications for strong earthquake activity in Turkey

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Geodesy and Geodynamics 2024年第3期15卷 209-218页

作者： Yuhang Pan shi Chen Wen shi Institute of Geophysics China Earthquake AdministrationBeijing 100081China beijing baijiatuan Earth Science National Observation and Research Station Beijing 100095China

On February 6, 2023, the doublet earthquake including two main shocks with magnitudes m_(W)7.8 and m_(W)7.5, occurred near the western side of the East Anatolian Fault at the southeast boundary of the Anatolian Plateau in Turkey. based on the WGm2012 bouguer gravity anomaly data and the Etopo1topography data, this study first introduced a joint inversion of admittance and coherence functions and used the bayesian optimal parameter estimation method to obtain the effective elastic thickness Teand loading ratio F of the lithosphere for various tectonic units in the Anatolian Plateau. Secondly, we discussed the characteristics and influencing factors of the lithospheric mechanical strength and analyzed its relationship with seismic activity. The lithospheric mechanical strength of the Anatolian Plateau showed clear lateral heterogeneity and a "weak-strong-weak" spatial pattern from east to west,reflecting various tectonic processes. At last, the strong seismic activity was found where the lithospheric strength was low in the Anatolian Plate. We also incorporated GPS strain rate and other results to investigate the tectonic background and primary causes of the m_(W)7.8 and m_(W)7.5 doublet earthquakes in Turkey. The results have a good insight into urban safety design in the Turkish region, including postdisaster rehabilitation, earthquake hazard assessment, and loss reduction.

关键词： Effective elastic thickness Anatolian plateau Turkey doublet earthquakes bayesian optimization

Stable carbon isotope composition and intrinsic water use efficiency in plants along an altitudinal gradient on the eastern slope of Yulong Snow mountain, China

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Ecological Processes 2024年第2期13卷 218-230页

作者： Feng Jiang Tao Pu Zi-Jing Xue Yan-Wei ma Xiao-Yi shi Fu-Xi shi College of Geography and Environmental Sciences Zhejiang Normal University Yulong Snow mountain Glacier and Environment Observation and Research Station/State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of Forestry Jiangxi Agricultural University

background Stable carbon isotope composition(δ13Cp) can be used to estimate the changes in intrinsic water use efficiency（iWUE） in plants,which helps us to better understand plants' response strategies to climate *** study focused on the variations in δ13Cpand iWUE for the different life-form plants（i.e.,herbs,shrubs,and trees）along an altitudinal gradient（3300,3600,3900,4100,4300,and 4500 m） on the eastern slope of Yulong Snow mountain,southeastern margin of the Qinghai-Tibet *** response mechanisms of δ13Cpand iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain *** The δ13Cpvalues of plants on the eastern slopes of Yulong Snow mountain ranged from-30.4‰to-26.55‰,with a mean of-28.02‰,indicating a dominance of *** δ13Cpand iWUE values varied among different life-form plants in the order of herbs> shrubs> trees,particularly in 3600,3900,and 4300 ***δ13Cpand iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air *** two parameters for trees exhibited a trend of initial decrease followed by an increase with *** 3900 m,the δ13Cpand iWUE values decreased with altitude,influenced by soil ***,above 3900 m,the two parameters increased with altitude,mainly regulated by air *** addition,iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio,especially for herbs and trees,suggesting that P plays a key role in modulating iWUE in this *** The diffe rentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature,soil moisture,and leaf P content in the Yulong Snow *** results provide valuable insights into understanding the wate r-carbon relationships in high-altitude ecosystems.

关键词： Stable carbon isotope Water use efficiency Altitude Life form Yulong Snow mountain